This invention relates to a sealing assembly for sealing cannulas used in medical procedures. More particularly, the present invention relates to medical cannulas configured to allow passage of medical devices therethrough while maintaining an airtight seal.
Laparoscopic surgical procedures typically involve pneumatic inflation of a patient's abdominal cavity to increase the accessibility of organs in the abdominal cavity. A cannula is positioned to extend through the abdominal wall of the patient, and secondary cannulas, including graspers, tweezers, baskets, or other medical devices can be inserted through the cannula to manipulate abdominal organs. To prevent egress through the cannula of air or liquid from the abdominal cavity of the patient, a mechanism for sealing the cannula is required. Such a sealing mechanism must still allow passage through the cannula of medical devices for efficient operation.
Mechanisms for sealing cannulas, tubes, channels, or the like are known in the art. For example, Patton et al., U.S. Pat. No. 4,886,507, describes a Y-connector for use in angioplasty procedures. The Y-connector has disposed in its main passage a socket that receives a Tuohy-Borst O-ring, and a cap with a spigot projecting from it. The cap is threaded onto an outside surface of a socket so that it can be screwed down to bring the spigot into contact with the Touhy-Borst ring to compress it. When the spigot is engaged with the Touhy-Borst ring, flow of blood around external surfaces of the ring, between the O-ring and the socket, is blocked. Axially spaced from, and in alignment with, the Touhy-Borst O-ring, is a membrane having a circular opening to receive and seal a catheter.
Krauter et al., U.S. Pat. No. 4,649,904, discloses a disposable seal having a luer lock and fitting for use with a biopsy channel of an endoscope. A seal is unitarily molded of a soft elastomer to have a double seal arrangement. The seal is formed by an aperture end wall and a one-way opening slit through a plate or web behind an end wall.
Hosono, U.S. Pat. No. 4,240,411, discloses a device for sealing an endoscope channel. The sealing device includes a hollow cylindrical member connected at one end to a proximal end of a channel disposed in the sheath of an endoscope, and a tubular member of an elastic material disposed in a hollow cylindrical member. The tubular member is connected at one end sealingly to another end of a hollow cylindrical member. The other end of the tubular member is bent to form a sealing portion that prevents air introduced into a body cavity from flowing back through the channel.
McLaughlin, U.S. Pat. No. 4,096,860, relates to an encatheter adapted for biaxial flow for receipt of a syringe at one end with the main axial passage interconnecting a plastic teflon insertion conduit at the other end and adapted for placement in a blood vessel with a needle. A valve member 38 is received in a cavity 24 defined in a hub 10. The valve member 38 includes a circular or cylindrical wall portion 40 tapering down to a nipple-like element 42 having a slit 44 therethrough. Ordinarily, the slit 44 is in a closed condition to provide for an elastomeric valving in the form of a one-way valve, so that flow can only take place after the valve member 38 has been separated by a tubular member passing therethrough, or by positive pressure.
Muto, U.S. Pat. No. 4,475,548, relates to a fitting for endotracheal apparatus to receive an endoscopic tube. A fitting 25 includes a foam body 31 embraced within a sleeve 30. The foam body 31 is slit end to end, preferably diametrally and preferably not to the edge, by a slit 46. The foam body 31 can be compressed both radially and axially.
Merry et al., U.S. Pat. 4,929,235, describes a self-sealing percutaneous tube (e.g. a catheter tube) having a sealing mechanism to prevent blood or fluid leakage. The sealing mechanism includes a space sealing gasket adapted to surround the tube, with a distal sealing element being planar and having a slit. A proximal sealing element is also provided, the proximal sealing element is conical, and has an annular opening at its distal and small end. Optionally, the percutaneous tube includes a side arm flushing member or a female luer lock connection at its proximal end.
O'Neill, U.S. Pat. No. 4,436,519, discloses a hemostasis valve that includes a body having a central passage. A seal having a central aperture therein is mounted in the central passage, along with a diaphragm having a wall member with a slit therein. The diaphragm wall member has an inner bottom diaphragm surface, an outer diaphragm surface, and the slit extends from the inner bottom diaphragm surface to the outer bottom diaphragm surface. Catheters can be forced through the diaphragms' slit and can be withdrawn, allowing the diaphragm slit 12 to close.
Other types of hemostasis valves are known. For example, hemostasis valves are disclosed U.S. Pat. No. 5,000,745; U.S. Pat. No. 4,430,08-; U.S. Pat. No. 4,626,245; and, U.S. Pat. No. 4,000,739.
Other valves for use in medical instruments, tubing, and/or stoppers or chromatographic injectors are disclosed in, for example, U.S. Pat. No. 4,673,393; U.S. Pat. No. 4,084,718; U.S. Pat. No. 4,515,752; U.S. Pat. No. 4,422,860; and, U.S. Pat. No. 4,013,310.
A sealing assembly for sealing a cannula used in medical procedures is provided. The cannula is configured to allow passage therethrough of medical devices. Contemplated medical devices can include secondary cannulas for injection or extraction of fluids, needles, graspers, tweezers, cutters, knives, baskets, or other conventional medical instrumentation. Typically, the cannula is disposable, and is attached to a disposable conduit piece formed to define at least one channel. Generally speaking, the present invention comprises a unique combination of compressible annular seal valve and a flap-type valve (such as a two-flap duckbill valve) in series with the annular seal valve to allow opening and closure of the one channel and sealably permit passage of medical instruments through said channel.
A compressible annular seal is positioned in the at least one channel to allow passage through its central aperture of a medical device. A mechanism is provided for compressing the compressible annular seal to provide an airtight seal across the at least one channel. Preferably, this mechanism is reversible, so that the seal can be allowed to return to its uncompressed state after withdrawal of the medical device.
In addition to the compressible annular seal, a secondary sealing mechanism that includes a flap valve (such as a two-flap duckbill valve) is provided. The duckbill flap valve is positioned in the at least one channel adjacent to the compressible annular seal to receive the medical device after its insertion through the central aperture of the compressible annular seal. The duckbill flap valve has at least first and a second flaps biased to sealingly engage each other, with the first and second flaps being configured to move apart to permit passage therethrough of a medical device inserted through the channel of the conduit piece.
In preferred embodiments, the compression mechanism of the sealing assembly includes a first annular wall defined by the conduit piece. A movable compression piece is formed to define a second annular wall, with the movable compression piece being movable with respect to the conduit piece to compress the compressible annular seal between its second annular wall and the first annular wall. Preferably, the movable compression piece is screwingly attached to the conduit piece by provision of external threads on the conduit piece, and internal threads on the movable compression piece to threadingly engage the external threads of the conduit piece.
Provision of an intermediary conduit piece optionally having multiple fluid passageways is not required for practice of the present invention. Alternatively, the present invention is a sealing assembly for pneumatically sealing a channel defined through a disposable cannula used in medical procedures, with the channel of the disposable cannula allowing passage therethrough of medical devices. The sealing assembly includes a compressible annular seal for sealing the channel, a mechanism for compressing the compressible annular seal to provide an airtight seal around a medical device inserted through the compressible annular seal, and a duckbill flap valve positioned adjacent to the compressible annular seal. The duckbill flap valve has first and a second flaps biased to sealingly engage each other, the first and second flaps being configured to move apart to permit passage therethrough of a medical device first inserted through the annular seal and into the channel of the disposable cannula.